Project Summary The Developmental Origins of Health and Disease theory (DOHaD) theory postulates that exposure to prenatal stressors during critical periods of early development could lead to permanent alterations of the developing tissues, which may increase the risk for future cardiometabolic and psychiatric disorders. Although the biological mechanisms that mediate these effects are not completely understood, recent studies indicate that epigenetic mechanisms and early life microbiome could be important mechanistic mediators in the DOHaD. On September 20, 2017, Puerto Rico was completely devastated by Hurricane Maria, a Category 4 storm that wiped out electric power, water and food supplies, health care services and communications for several weeks up to months in the entire island. The threat to life and the loss associated with this hurricane are a source of increased prenatal maternal stress (PNMS) that could lead to significant mental health problems in the mother. Our general hypothesis is that children who were prenatally exposed to psychosocial and environmental stressors associated with Hurricane Maria in Puerto Rico could have a higher risk for cardiometabolic and psychological health outcomes later in life, which could be partially due to early-life biological modifications in the epigenetic and/or microbiome profiles in response to these stressors. To begin testing this hypothesis we propose a cross-sectional study to recruit a prospective birth cohort of 200 infants 12 to 15 months of age who were prenatally exposed to Hurricane Maria and their mothers and to collect detailed baseline data regarding potential hurricane-related prenatal stressors, as well as biological samples and clinical assessments. We will evaluate PNMS, defined as the presence of post-disaster maternal depression and/or PTSD, as well as hurricane experiences, living conditions, and nutrition, and evaluate associations with perinatal and early- life health outcomes. We will also compare the epigenetic and microbiome profiles between infants born to mothers with high vs. low PNMS.